It is a common technique to insulate pipe systems which carry hot or cold fluids to conserve on overall energy losses or consumption by the system. It has been the practice for many years to insulate pipe systems with insulative material covered by a sheet metal housing. An example of this structure is disclosed in U.S. Pat. No. 4,363,681. A pipe is enclosed by segments of insulation which are held in place by a rigid outer covering of sheet metal. As demonstrated with respect to the elbow of the pipe system shown in this patent, the sheet metal construction becomes rather complex. Normally when the elbow of such a pipe system requires servicing, the sheet metal has to be destroyed to gain access to the faulty component. Alternatively, the sheet metal construction may include buckle fasteners and hinge members which permit releasing of the sheet metal from the insulative material. However, once these systems become bent or twisted, they cannot be reused; hence reinsulating of that section of the pipe is required.
Pipe insulation systems, which involve reusable units having quick release fasteners or the like, are disclosed in U.S. Pat. Nos. 3,941,159 and 4,009,735. Both patents disclose the use of "Velcro" type fasteners for securing the insulation wrap around the pipe to be insulated. This arrangement is suitable for straight sections of pipe which do not involve complex shapes, such as elbows, valve assemblies, couplings and the like.
When it comes to insulating a valve assembly or other complex shape, an approach is disclosed in U.S. Pat. No. 4,207,918. This patent requires the use of several blanket components which are assembled to one another in sequence to complete the insulating of a valve body and bonnet, and also overlap the insulation of adjacent pipe portions. The use of belts and lacing to hold the unit in place detracts from the ability to release the insulation from the valve when service is required. Normally, the straps are cut with a knife hence requiring new straps when the valve is reinsulated. New straps are not always available. On the other hand, if an attempt is made to release the straps manually particularly if it is in cold temperatures, the task at time can become impossible particularly when the tradesman must wear gloves. After the insulating unit is disassembled and removed from the valve body, components can be lost or blown away in the wind and hence only partial reassembly of the unit is effected resulting in loss of insulative value.